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The Nature-Nurture Interactions Behind Eating Disorders


Research, decades of observation and record keeping are making it clear that eating disorder development is not owed to either nature (genetics) or nurture (environmental factors), but is owed to nature and nurture. Our genes and our environmental factors interact to create the level of risk.

Although genes alone do not determine the development of eating disorders, research has found that the disorders do run in families. Family studies have not clarified how much this familial pattern is genetically based and how much it is related to environmental factors. Twin studies, however, show that susceptibility to anorexia, bulimia and binge eating are influenced by genetics.

Gene-Environment Interactions

Genes and the environment can interact both passively and actively to determine a person’s level of risk for eating disorders.

  • Passive gene-environment interaction refers to the fact that our biological parents are the same people who create our growing-up environment (except in adoption). So the parents who do or do not pass on a genetic liability for an eating disorder are also going to be modeling their own attitudes and behaviors to the children, including those related to food.
  • Active gene-environment interaction refers to individuals who are born with a genetic vulnerability to developing an eating disorder and put themselves in environments that emphasize a person’s looks and thinness. Examples of these environments are gymnastics, ballet, acting and modeling.

Four Types of Risk Factors

The factors that influence the development of an eating disorder can be grouped four ways. A person’s overall susceptibility to eating disorders is his or her unique sum of all four factors.

  1. Genetic protective factors are those genetic influences that buffer us from eating disorders. For instance, if an individual is genetically constituted to be thin, this might protect him or her from going on diets even if his or her peers do.
  2. Genetic risk factors are those genetic influences that make us vulnerable to eating disorders. For example, an individual having an aunt with anorexia might have inherited a genetic vulnerability to the disorder.
  3. Environmental protective factors are the environmental influences that buffer us from eating disorders. For instance, having good communication between parents and a child gives that child an opportunity to discuss the pressure to lose weight for ballet class.
  4. Environment risk factors are those environmental influences that make us vulnerable to an eating disorder. For example, a high school gymnastics coach might insist that everyone on the team lose five pounds to improve performance, having the team members weigh in at each practice.

Eating Disorder Prevention

Although genes play a role in eating disorders, research has not taught us enough to treat or prevent eating disorders through genetic intervention. What parents, teachers, friends and coaches can do to help prevent eating disorders is create protective environments and model protective attitudes that buffer vulnerable individuals from the risks.

Source: Nature and Nurture